A pulsed detonation engine may include a detonation tube for receiving fuel and an oxidizer to be detonated therein, one or more fuel-oxidizer injectors for injecting the fuel and oxidizer into the detonation tube, one or more purge air injectors for injecting purge air into the detonation tube for purging the detonation tube, and an ignition for igniting the fuel and oxidizer in the detonation tube so as to initiate detonation thereof. The detonation tube has an upstream end, a downstream end, and an axially extended portion extending from the upstream end to the downstream end and having a perimeter. The fuel-oxidizer injectors and purge air injectors may be disposed at least along the axially extended portion. The ignition may include a plurality of igniters disposed at or near the perimeter of the axially extended portion, spaced about the perimeter, at or near the upstream end of the detonation tube.

A pulsed detonation engine may include a detonation tube for receiving fuel and an oxidizer to be detonated therein, one or more fuel-oxidizer injectors for injecting the fuel and oxidizer into the detonation tube, one or more purge air injectors for injecting purge air into the detonation tube for purging the detonation tube, and an ignition for igniting the fuel and oxidizer in the detonation tube so as to initiate detonation thereof. The detonation tube has an upstream end, a downstream end, and an axially extended portion extending from the upstream end to the downstream end and having a perimeter. The fuel-oxidizer injectors and purge air injectors may be disposed at least along the axially extended portion. The ignition may include a plurality of igniters disposed at or near the perimeter of the axially extended portion, spaced about the perimeter, at or near the upstream end of the detonation tube.

A pulse combustor system for operating pulse combustors in anti-phase. The pulse combustor system includes two pulse combustors connected at their combustion chambers by a connecting tube. Each of the pulse combustors has a fundamental oscillation mode and one or more additional oscillation modes when operated in isolation. The connecting tube has a length corresponding to of the fundamental oscillation mode wavelength.

An accessory power unit assembly includes a combustor assembly that includes a pulse detonation tube that defines a curved passage between an inlet that receives a compressed airflow and a discharge end. The detonation tube operates as a resonant cavity to sustain a standing pressure wave. Fuel injected into the pulse detonation tube is timed to coincide with movement of a standing wave toward a discharge end. The standing wave provides an increase in pressure of an output exhaust gas driving the turbine without a corresponding increase in load.

A gas turbine combustor includes: a tubular body; an air passage; and a resonator. The air passage includes: an upstream region that extends along an outer peripheral surface of the tubular body; a downstream region that extends along an inner peripheral surface of the tubular body and is located at a first side of the combustion chamber in the axial direction; and a direction change region that connects the upstream region to the downstream region in a radial direction of the tubular body and is adjacent to the upstream region such that an area of a section of the air passage which is orthogonal to the axial direction changes at a position between the upstream region and the direction change region. The opening is open toward a space of the air passage which is located downstream of the upstream region.

A gas turbine combustor includes: a tubular body; an air passage; and a resonator. The air passage includes: an upstream region that extends along an outer peripheral surface of the tubular body; a downstream region that extends along an inner peripheral surface of the tubular body and is located at a first side of the combustion chamber in the axial direction; and a direction change region that connects the upstream region to the downstream region in a radial direction of the tubular body and is adjacent to the upstream region such that an area of a section of the air passage which is orthogonal to the axial direction changes at a position between the upstream region and the direction change region. The opening is open toward a space of the air passage which is located downstream of the upstream region.

A wave disc engine apparatus is provided. A further aspect employs a constricted nozzle in a wave rotor channel. A further aspect provides a sharp bend between an inlet and an outlet in a fluid pathway of a wave rotor, with the bend being spaced away from a peripheral edge of the wave rotor. A radial wave rotor for generating electricity in an automotive vehicle is disclosed in yet another aspect.

A wave disc engine apparatus is provided. A further aspect employs a constricted nozzle in a wave rotor channel. A further aspect provides a sharp bend between an inlet and an outlet in a fluid pathway of a wave rotor, with the bend being spaced away from a peripheral edge of the wave rotor. A radial wave rotor for generating electricity in an automotive vehicle is disclosed in yet another aspect.

A panel is provided for attenuating noise. This panel includes a first skin, a second skin and a cellular core. The cellular core may be connected to and form a plurality of cavities between the first skin and the second skin. The cellular core may include a wall and a septum. The cavities may include a first cavity and a second cavity. The septum may fluidly divide the first cavity into a first sub-cavity and a second sub-cavity. One or more perforations in the first skin may be fluidly coupled with the first sub-cavity. One or more perforations in the wall may fluidly couple the first sub-cavity with at least a region of the second cavity.

A pulse combustor system for efficiently operating a pulse combustor. The pulse combustor system includes the pulse combustor and a duct. The pulse combustor has a combustion chamber defining an internal space, a conduit having a first end in fluid communication with the internal space and a second end in fluid communication with an environment outside of the pulse combustor system, and a fuel injector configured to inject fuel into the internal space of the combustion chamber. The duct has two openings, with one opening disposed adjacent to the second end of the conduit. The pulse combustor system has an average operating frequency, and the duct has a length that is about one quarter of a wavelength corresponding to the average operating frequency. The pulse combustor and the duct each has a central longitudinal axis, and the two axes are substantially aligned.